The present invention is generally directed to releasing locked components of a pin-clutch mechanism and is particularly directed to an improvement in apparatus for magnetically releasing locked components of a theft-deterrent device of the type in which a pin-anchoring component and a clutch-containing component are adapted to be locked together on opposite sides of a portion of a protected article to prevent unauthorized removal of the device from the article.
Examples of pin-clutch mechanisms that are used in theft-deterrent devices are described in U.S. Pat. No. 4,523,356 to Lincoln H. Charlot, Jr. and U.S. patent application Ser. No. 07/529,940 filed May 29, 1990 by Lincoln H. Charlot, Jr. application Ser. No. 07/529,940 further describes an apparatus for releasing the pin-clutch mechanism described therein. The clutch mechanism described in U.S. Pat. No. 4,523,356 and application Ser. No. 07/529,940 includes a ferromagnetic anvil having an axial bore for axially receiving the pin; receiving means axially aligned with the anvil for axially receiving a said pin that is axially received by the bore of the anvil, wherein the anvil is longitudinally movable along its bore axis with respect to the receiving means; and a spring for forcing the anvil toward a first end of the receiving means; clutching means engaging the anvil and forced by the anvil toward the first end of the receiving means when the anvil is forced toward the first end of the receiving means by the spring, with the clutching means being disposed to apply radial pressure against said pin to firmly clutch the pin when the clutching means are forced toward the first end of the receiving means and thereby restrain the pin from release from the clutching means. An apparatus for releasing the pin-clutch mechanism described in U.S. Pat. No. 4,523,356 includes a magnet disposed for axially applying magnetic flux to the anvil to overcome the force of the spring and force the anvil to move away from the first end of the receiving means.
The clutch mechanism described in application Ser. No. 07/529,940 further includes a radially disposed pole piece for directing magnetic flux applied radially by means external to the mechanism so that at least a predetermined amount of said radially applied magnetic flux is so concentrated axially in the anvil as to overcome the force of the spring and force the anvil to move away from the first end of the receiving means. The pole piece of the clutch mechanism includes a ferromagnetic disc-shaped ring disposed adjacent the first end of the receiving means in a plane that is perpendicular to said axis.
The releasing apparatus described in application Ser. No. 07/529,940 includes an axially disposed magnet for providing in excess of said predetermined amount of magnetic flux; a pole piece coupled to the magnet and disposed coaxially with the magnet for applying in excess of said predetermined amount of magnetic flux radially toward the axis of the magnet in a plane that is beyond the magnet; and a seat for receiving the clutch mechanism in a position in which the pole piece of the clutch mechanism is so disposed in relation to the pole piece of the releasing apparatus as to direct magnetic flux applied radially by the pole piece of the releasing apparatus and to concentrate at least said predetermined amount of said radially applied magnetic flux in the anvil to thereby overcome the force of the spring and force the anvil to move away from the first end of the receiving means to thereby relax the radial pressure applied against the pin by the clutching means so that the pin-anchoring component can be released from the clutch-containing component. The pole piece of the releasing apparatus terminates in a rim that is adjacent the ferromagnetic disc-shaped ring of the clutch mechanism when said clutch-containing component is received by the seat.
The attactive force applied to the clutch-containing component by the magnet of the releasing apparatus makes it difficult to remove the clutch-containing component from the seat of the releasing apparatus following release and removal of the pin-anchoring component. Such difficulty is compounded when using the releasing apparatus described in application Ser. No. 07/529,940 because the pole piece of the releasing apparatus is positioned about the sides of the clutch-containing component, whereby it is difficult to grip the clutch-containing component to remove the clutch-containing component from the seat of the releasing apparatus following release and removal of the pin-anchoring component.